This invention pertains to a method for reducing the flammability of an aluminum complex grease by adding certain calcium oxides to the grease. 2. Description of Related Art
The addition of various calcium oxides to greases is known. For example, U.S. Pat. No. 3,933,657 discloses that from about 1 to 20 wt % lime is a conventional extreme pressure additive to a wide variety of greases, including greases having an aluminum base soap thickener. Specific properties of the lime are not discussed. As another example, U.S. Pat. No. 4,379,062 discloses a thread sealing and lubricating composition which contains 8-25% finely divided copper flakes, 5-20% finely divided aluminum particles, and 4-15% non-metallic, non-carbon powder suspended in a petroleum vehicle. The vehicle is preferably a petroleum stock or grease containing a metallic soap or an inorganic thickening agent. No mention is made of an aluminum complex grease as the thickener. In still another example, U.S. Pat. No. 2,719,826 discloses that the antiwear characteristics of an aluminum complex grease can be enhanced by dispersing from 0.02 to 7% calcium oxide or hydroxide therein, with the dispersion being stabilized by a polyvalent metal sulfonate.
However, none of these references disclose that the flammability of a grease having an aluminum complex thickener can be significantly reduced by incorporating specific amounts of certain calcium oxides therein.